1. Technical Field
Example embodiments of the present invention relate in general to wireless local area network (WLAN) technology, and more particularly, to a technology for transmitting and receiving a frame including multiplexed data units.
2. Related Art
With the development of information and communication technology, a variety of wireless communication technologies are under development. Among these, a WLAN is a technology for enabling wireless Internet access through a portable terminal, such as a personal digital assistant (PDA), a laptop computer, a portable multimedia player (PMP), a smart phone, or a tablet personal computer (PC), in a home, a company, or a specific service providing area based on radio frequency technology.
Standards of a WLAN are being developed as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. A WLAN technology conforming to the IEEE 802.11a standard operates based on orthogonal frequency division multiplexing (OFDM), and may provide a maximum transmission rate of 54 Mbps in the 5 GHz band. A WLAN technology conforming to the IEEE 802.11b standard operates based on direct sequence spread spectrum (DSSS), and may provide a maximum transmission rate of 11 Mbps in the 2.4 GHz band. A WLAN technology conforming to the IEEE 802.11g standard operates based on OFDM or DSSS, and may provide a maximum transmission rate of 54 Mbps in the 2.4 GHz band.
A WLAN technology conforming to the IEEE 802.11n standard operates in the 2.4 GHz band and the 5 GHz band based on OFDM, and may provide a maximum transmission rate of 300 Mbps to four spatial streams when multiple-input multiple-output OFDM (MIMO-OFDM) is used. The WLAN technology conforming to the IEEE 802.11n standard may support a channel bandwidth up to 40 MHz, and in this case, it is possible to provide a maximum transmission rate of 600 Mbps.
The prevalence of such a WLAN and the diversification of applications using a WLAN are leading to an increase in the necessity for a new WLAN technology for supporting a higher throughput than the data processing speed supported by IEEE 802.11n. A very high throughput (VHT) WLAN technology is one of the IEEE 802.11 WLAN technologies that have been proposed to support a data processing speed of 1 Gbps or more. Among them, IEEE 802.11ac is under development as a standard for providing a VHT in a band of 5 GHz or less, and IEEE 802.11ad is under development as a standard for providing a VHT in a 60 GHz band.
Recently, the number of stations (STAs) associated to a basic service set (BSS) of a WLAN has been drastically increasing, and collisions between STAs in a BSS have been increasing accordingly. In this situation, a transmission and reception method for efficiently exchanging data between STAs is necessary.